MCF-7 Human Breast Carcinoma Cells Research Articles

Micro Total Bioassay System for Ingested Substances: Assessment of Intestinal Absorption, Hepatic Metabolism, and Bioactivity

Oral medicines and food constituents are absorbed in the intestine and metabolized in the liver, after which they exhibit their activity toward a target tissue. Micromodels of human tissues were developed to mimic these processes and bioactivities. By integrating the micromodels, we realized a micro total bioassay system for oral substances; this system comprised a microintestine, microliver, and the target components. The microchip was composed of a slide glass and polydimethylsiloxane (PDMS) sheets with microchannels fabricated by photolithography. Caco-2 cells were cultured in the intestine component, and HepG2 cells, in the liver component. The human breast carcinoma MCF-7 cells were cultured in the target component, and the activities of anticancer agents and estrogen-like substances were successfully assayed. By using this system, the overall properties of the ingested cyclophosphamide, epirubicin, 17-β estradiol, and soy isoflavone, i.e., their intestinal absorption, hepatic metabolism, and bioactivity toward target cells, could be assayed with operative ease. Further, the assay time and cell consumption were reduced compared to those in conventional in vitro bioassay systems.

Genome-wide Analysis of Novel Splice Variants Induced by Topoisomerase I Poisoning Shows Preferential Occurrence in Genes Encoding Splicing Factors

RNA splicing is required to remove introns from pre-mRNA, and alternative splicing generates protein diversity. Topoisomerase I (Top1) has been shown to be coupled with splicing by regulating serine/arginine-rich splicing proteins. Prior studies on isolated genes also showed that Top1 poisoning by camptothecin (CPT), which traps Top1 cleavage complexes (Top1cc), can alter RNA splicing. Here, we tested the effect of Top1 inhibition on splicing at the genome-wide level in human colon carcinoma HCT116 and breast carcinoma MCF7 cells. The RNA of HCT116 cells treated with CPT for various times was analyzed with ExonHit Human Splice Array. Unlike other exon array platforms, the ExonHit arrays include junction probes that allow the detection of splice variants with high sensitivity and specificity. We report that CPT treatment preferentially affects the splicing of splicing-related factors, such as RBM8A, and generates transcripts coding for inactive proteins lacking key functional domains. The splicing alterations induced by CPT are not observed with cisplatin or vinblastine and are not simply due to reduced Top1 activity, as Top1 downregulation by short interfering RNA did not alter splicing like CPT treatment. Inhibition of RNA polymerase II (Pol II) hyperphosphorylation by 5,6-dichloro-1-β-d-ribofuranosylbenzimidazole (DRB) blocked the splicing alteration induced by CPT, which suggests that the rapid Pol II hyperphosphorylation induced by CPT interferes with normal splicing. The preferential effect of CPT on genes encoding splicing factors may explain the abnormal splicing of a large number of genes in response to Top1cc.

Role for ezrin in breast cancer cell chemotaxis to CCL5

This study was undertaken to observe the effects and the possible mechanism of membrane-cytoskeleton linker ezrin on the chemokine CC chemokine ligand 5 (CCL5)-induced invasive ability in human breast carcinoma MCF-7 cells. RNA interference (RNAi) using ezrin small hairpin RNAs (ezrin shRNA) was used to analyze the role of ezrin in the regulation of this CCL5-induced malignant behavior of MCF-7 cells. The effects of recombinant human CCL5 (rhCCL5) on the cell's invasive ability were detected by transwell assay. Western blotting was performed to examine the expression of the total and the phosphorylated ezrin at protein level. The CCL5-induced changes in the organization of the actin cytoskeleton in the transfected cells were determined using confocal microscopy. Flow cytometry was used to detect the cell cycle. MTT method was used to detect the proliferation of the cells. We found that the MCF-7 cells responded chemotactically to CCL5 in a dose- and time-dependent manner. After RNAi treatment, the proliferation was inhibited and the cell proportion in G2-M phase decreased. The CCL5-induced cell motility and invasiveness were obviously inhibited by the silencing of ezrin. In addition, the CCL5 induced a significant up-regulation in the total and the phosphorylated ezrin expression in MCF-7 cells, whereas in the presence of ezrin silencing, the CCL5 induced only a slight increase in the total and the phosphorylated ezrin expression. CCL5 was shown to induce changes in the organization of the actin cytoskeleton and the level of F-actin in MCF-7 cells, and the silencing of ezrin could inhibit these changes. Collectively, our data further show that CCL5 induced invasiveness in MCF-7 cells. These data indicate a potential role for ezrin in the processes of the CCL5-induced breast cancer cell migration, invasiveness and metastasis. It is suggested that ezrin may act as downstream effector of CCL5 and a new anti-invasive therapeutic target for human breast cancer.

Role for ezrin in breast cancer cell chemotaxis to CCL5

This study was undertaken to observe the effects and the possible mechanism of membrane-cytoskeleton linker ezrin on the chemokine CC chemokine ligand 5 (CCL5)-induced invasive ability in human breast carcinoma MCF-7 cells. RNA interference (RNAi) using ezrin small hairpin RNAs (ezrin shRNA) was used to analyze the role of ezrin in the regulation of this CCL5-induced malignant behavior of MCF-7 cells. The effects of recombinant human CCL5 (rhCCL5) on the cell's invasive ability were detected by transwell assay. Western blotting was performed to examine the expression of the total and the phosphorylated ezrin at protein level. The CCL5-induced changes in the organization of the actin cytoskeleton in the transfected cells were determined using confocal microscopy. Flow cytometry was used to detect the cell cycle. MTT method was used to detect the proliferation of the cells. We found that the MCF-7 cells responded chemotactically to CCL5 in a dose- and time-dependent manner. After RNAi treatment, the proliferation was inhibited and the cell proportion in G2-M phase decreased. The CCL5-induced cell motility and invasiveness were obviously inhibited by the silencing of ezrin. In addition, the CCL5 induced a significant up-regulation in the total and the phosphorylated ezrin expression in MCF-7 cells, whereas in the presence of ezrin silencing, the CCL5 induced only a slight increase in the total and the phosphorylated ezrin expression. CCL5 was shown to induce changes in the organization of the actin cytoskeleton and the level of F-actin in MCF-7 cells, and the silencing of ezrin could inhibit these changes. Collectively, our data further show that CCL5 induced invasiveness in MCF-7 cells. These data indicate a potential role for ezrin in the processes of the CCL5-induced breast cancer cell migration, invasiveness and metastasis. It is suggested that ezrin may act as downstream effector of CCL5 and a new anti-invasive therapeutic target for human breast cancer.

Dose-related effects of Quercetin in the human breast carcinoma MCF-7 cell line

Quercetin is a flavonol present at high levels in onions, apples, tea and red wine. Although quercetin has been epidemiologically associated with bioactive protective effects, this compound has also been shown to be mutagenic and toxic in short-term in vitro test systems. This study evaluated quercetin for toxicity in the MCF-7 cell line in the presence or absence of benzo[a]pyrene (B[a]P), a known DNA-reactive carcinogen. In the clonogenic assay, 2.5 × 10 2

Differential Up-regulation of MAP Kinase Phosphatases MKP3/DUSP6 and DUSP5 by Ets2 and c-Jun Converge in the Control of the Growth Arrest Versus Proliferation Response of MCF-7 Breast Cancer Cells to Phorbol Ester

Different levels of regulation account for the inactivation of MAP kinases by MAPK phosphatases (MKPs), in a cell type- and stimuli-dependent manner. MCF-7 human breast carcinoma cells treated with the phorbol 12-myristate 13-acetate (PMA) suffer growth arrest and show morphological alterations, which depend on the activation of the ERK1/2 MAP kinases. MKP3/DUSP6 and DUSP5 MAP kinase phosphatases, two negative regulators of ERK1/2, were specifically up-regulated in MCF-7 and SKBR3 cells in response to PMA. MKP3 and DUSP5 up-regulation required the prolonged activation of the ERK1/2 pathway, and correlated with the shutdown of this route. MKP3 induction relied on the activation of the Ets2 transcription factor, whereas DUSP5 induction depended on the activation of c-Jun. Diminishing the expression of MKP3 and DUSP5 raised the activation of ERK1/2, and accelerated growth arrest of PMA-treated MCF-7 cells. Conversely, MCF-7 cell lines expressing high levels of MKP3 or DUSP5 did not undergo PMA-triggered growth arrest, displayed a migratory phenotype, and formed colonies in soft agar. We propose that the differential up-regulation of MKP3 by Ets2 and of DUSP5 by c-Jun may converge in similar functional roles for these MAP kinase phosphatases in the growth arrest versus proliferation decisions of breast cancer cells.

Neospora caninum: In vitro culture of tachyzoites in MCF-7 human breast carcinoma cells

The development of Neospora caninum tachyzoites, an apicomplexan protozoan parasite, was studied in vitro using the human breast carcinoma cell 7 (MCF-7) as the host cell line. The extracellular NC-1 tachyzoites in MCF-7 cells were observed and counted daily for 6 consecutive days post-infection to establish the growth curve. The intracellular parasites were observed by acridine orange staining using Laser scanning confocal microscope. The results indicated that NC-1 tachyzoites invaded MCF-7 cells and multiplied intracellularly. The number of extracellular NC-1 tachyzoites started to increase rapidly around day 3 and reached the maximum number around day 4. Results from the present study suggested that MCF-7 cells were susceptible to NC-1 tachyzoites and could be used as an alternative cell line for in vitro studies.

The immunoglobulin-like cell adhesion molecule hepaCAM is cleaved in the human breast carcinoma MCF7 cells

We previously reported the identification and characteristics of hepaCAM, a new immunoglobulin-like adhesion molecule. Frequently lost in diverse tumors, hepaCAM exhibits antiproliferative effects on cancer cells and promotes cell-extracellular matrix (ECM) interactions when re-expressed. Herein, we demonstrate for the first time that hepaCAM is cleaved in the human breast carcinoma MCF7 cells, generating a fragment containing mainly the cytoplasmic domain. The phorbol ester phorbol 12-myristate 13-acetate (PMA) did not affect the cleavage of hepaCAM. However, calcium-influx promoted hepaCAM cleavage independent of PKC. In addition, inhibitors of proteasome and cysteine proteases strongly suppressed the cleavage of hepaCAM, indicating the involvement of proteasome, calpain-1 and cathepsin B. Furthermore, we showed that functions of hepaCAM were impaired when the cytoplasmic domain was cleaved. The truncation mutant of hepaCAM failed to promote cell-ECM adhesion and migration, and lost the inhibitory effects on cell growth, suggesting a regulatory role of the cleavage in hepaCAM functions.

Novel Surfactant‐like Hypocrellin Derivatives to Achieve Simultaneous Drug Delivery in Blood Plasma and Cell Uptake

Water-soluble derivatives of hypocrellins can be safely delivered in blood plasma but lose their photodynamic activity in vivo due to poor cell uptake, while hydrophobic derivatives retaining their activity may aggregate in the blood plasma and block vascular networks. Considering both drug delivery and biological activity, surfactant-like hypocrellin B (HB) derivatives, sodium 12-2-HB-aminododecanoate (SAHB) and sodium 11,11'-5,8-HB-dimercaptoundecanoate (DMHB), were first designed and then synthesized in the current work. Both SAHB and DMHB were photoactive, generating free radicals and reactive oxygen species, as confirmed by EPR and chemical measurements. Most importantly, DMHB was not only readily soluble, allowing preparation of an intravenous injection solution at a clinically acceptable concentration, but it was also more photodynamic therapy (PDT) active to human breast carcinoma MCF-7 cells than its parent HB under irradiation. The photodynamic activity was exactly identical to the (1)O(2) quantum yield and was not reduced by the improved water solubility, suggesting an independent hydrophilicity or lipophilicity. To our knowledge, this is a new strategy that possesses general significance for converting hydrophobic photosensitizers into clinically usable PDT drugs.

Abstract 5219: Relationship between intratumoral drug distribution and tumor microenvironment

Abstract Purpose: Anticancer agents released from nanocarriers have to reach cancer cells in order to demonstrate their cytotoxic activity. The distribution pattern of anticancer agents can be affected by the tumor microenvironment which varies among different types of tumors. The purpose of this study is to delineate the relationship between drug transport and tumor microenvironmental factors, such as extracellular matrix (ECM) integrity. Such studies provide insight into the factors that hinder the accessibility of cargo molecules to cancer cells. Hypothesis: In tumors with a “permissive” ECM, small molecules are likely to diffuse farther after release from nanocarriers, while they are likely to be hindered in the tumors with denser ECM. Non-invasive monitoring of drug release and subsequent intratumoral distribution of the released drug can be visualized using a dual MR contrast technique capable of distinguishing between released and intact molecules in vivo. Methods: GdDTPA was used as a surrogate tracer for a water-soluble, small molecular-weight drug. Liposomes were used as the model nanocarrier in this study. Xenografts derived from the highly-invasive and metastatic MDA-MB-231 human breast carcinoma cell line, and weakly-metastatic MCF-7 human breast carcinoma cells were used. Liposomes encapsulating GdDTPA, iron particles, and rhodamine (Lip-Gd/Fe/Rho) were prepared using a sonication method, followed by extrusion. Orthotopic xenografts were grown in female SCID mice by injecting 3×106 of cancer cells into the mammary fat pad of the animal. All MR studies were carried out on a horizontal bore Bruker Biospec 9.4T spectrometer. MR images were acquired before, 30 min, and 23 hrs post-i.v. administration of Lip-Gd/Fe/Rho. To identify iron particles, a 3D fast low-angle shot (FLASH) sequence was used, while a 3D fast spin echo (RARE: Rapid Acquisition with Relaxation Enhancement) sequence with an effective echo time of 50 ms and five different repetition times was acquired to track GdDTPA released from liposomes. After completion of the MRI study, tumors were excised, fixed and were cut into 10μm sections for imaging with second harmonic generation multiphoton microscopy. Region of interest analysis were carried out on the MRI data. Results/Discussion: In vivo MRI results demonstrated that a decrease in T1 of the tumors was observed following i.v. administration of the Lip-Gd/Fe/Rho, indicating successful delivery and degradation of liposomes in the tumor. The comparison of differences in liposome delivery and its correlation with collagen-I density in the ECM of MDA-MB-231 and MCF-7 tumors is currently underway. Our results demonstrate the feasibility if using complementary imaging techniques to characterize the factors affecting intratumoral distribution of drug molecules after a release from nanocarriers. Acknowledgment: Supported by NIH grant R21 EB008162 (YK). Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5219.

Abstract 2485: Inhibitory effects of the water extract of Nelumbo Nucifera leaf on human breast carcinoma MCF-7 cells in vitro and in vivo

Abstract Over the passed decade, advances in understanding carcinogenesis have made possible the identification of the candidates of chemopreventive agents to be developed in targeting the key molecules. Lotus (Nelumbo nucifera Gaertn) is widely distributed in central and southern Taiwan. Its leaves are becoming popular as an ingredient of healthy beverages. Nelumbo nucifera Leaf extract (NLE) has been reported to exhibit different therapeutic effects, such as anti-oxidant and reduction of risks for cardiovascular disease. This study was aimed to investigate the antitumor effect of NLE on human MCF-7 cell line in vitro and in vivo. Qualitative analysis showed that the NLE contains several compounds using nine kinds of standard polyphenols by high-performance liquid chromatography (HPLC) method. The polyphenols present in identified compound of NLE were mainly gallic acid, rutin and quercetin. The MTT data showed no significant inhibition on growth of MCF-7 cells following NLE treatment, whereas flow cytometry revealed that the cell cycle was arrested at G0/G1 phase with a dose of 3 mg/ml in MCF-7 cells (approximately 86.54%). With western blotting, we found that treatment with NLE particularly induced p53 phosphorylation and p21 expression, and down-regulated expression of cyclins (cyclin D, cyclin E) and cyclin-dependent kinases (cdk2, cdk4) in a dose-dependent manner. The increased p21 also correlated with the decrease of cyclin D/cdk4 and cyclin E/cdk2 complexes, which was responsible for the high protein expression of Rb/E2F. Inactivation of fatty acid synthase (FAS) was shown in vitro and in vivo, implying that FAS was a potent regulator as well of NLE- mediated anti-carcinogenesis. The tumoricidal effect of NLE was further measured using a xenograft nude mice model. Treatment with NLE (0.5 and 1%) effectively reduced the tumor volume and tumor weight in the nude mice inoculated with MCF-7 cells when compared to the control tissue samples. These results confirmed that cell cycle arrest is sufficient to elicit tumor regression after NLE treatment. In conclusion, our studies indicate that NLE offers an anti-tumor activity and potentially can act as a chemotherapeutic agent. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2485.

Lead identification of conformationally restricted benzoxepin type combretastatin analogs: synthesis, antiproliferative activity, and tubulin effects

We have synthesized a series of polymethoxylated rigid analogs of combretastatin A-4 which contain a benzoxepin ring in place of the usual ethylene bridge present in the natural combretastatin products. The compounds display antiproliferative activity when evaluated against the MCF-7 and MDA human breast carcinoma cell lines. 5-(3-Hydroxy-4-methoxyphenyl)-4-(3,4,5-trimethoxyphenyl)-2,3-dihydro-benzoxepine (11g) was found to be the most potent product when evaluated against the MCF-7 breast cancer cell line. A brief computational study of the structure–activity relationship for the synthesized compounds is presented. These 4,5-diarylbenzoxepins are identified as potentially useful scaffolds for the further development of antitumor agents which target tubulin.

The effect of siRNA-Egr-1 and camptothecin on growth and chemosensitivity of breast cancer cell lines

We have examined the effects of a siRNA targeting the Egr-1, alone or in combination with the breast cancer therapeutic camptothecin (Cpt), in suppressing breast cancer cell survival and anchorage-independent growth in the breast cancer cell lines SK-BR3 and MCF-7. In mammary and lung tumors, as well as most normal tissues, Egr-1 expression is low, suggesting a possible relation between the low levels of Egr-1 and the development of mammary neoplasias. However, analyses of the expression of Egr-1 in breast carcinoma cells, SK-BR3 and MCF-7 demonstrated a relatively high expression of the endogenous Egr-1 in these cells. To investigate the effect of the blocking of the endogenous Egr-1 in breast cancer cells, we used small interfering RNA (siRNA) against Egr-1 alone or in combination with Cpt, and expected that the cell sensitivity to chemotherapeutic drug would increase, when blocked with the Egr-1 gene and treated with Cpt. Thus, we performed in vitro experiment to clarify the effect of Egr-1 on tumor cell lines growth. We made control and siRNA-Egr-1 using vector plasmids and then transfected SK-BR3 and MCF-7 cells. After treating the cells with siRNA-Egr-1, the cell lines were assayed with Cpt to confirm the effect of Egr-1 siRNA using the cell expression of mRNA and protein, proliferation assay and anchorage activity with soft agar. Human SK-BR3 and MCF-7 breast carcinoma cell growth and capacity of anchorage transfected with siRNA-Egr-1 or treated with cpt was slower than that of the control group. This effect was increased when the cells were given simultaneously siRNA and camptothecin. The results strongly suggest that siRNA-Egr-1 alone or in combination with camptothecin could be a potent antineoplastic agent in suppressing the growth of breast tumor despite the known role of Egr-1 as a tumor-suppressor in several other types of human cancers.

Hyul-Tong-Ryung suppresses PMA-induced MMP-9 expression by inhibiting AP-1-mediated gene expression via ERK1/2 signaling pathway in MCF-7 human breast cancer cells

Our previous study has demonstrated that the methanol extract of Hyul-Tong-Ryung (HM) specifically suppresses the phorbol 12-myristate 13-acetate (PMA)-induced matrix metalloproteinase-9 (MMP-9) production through the inhibition of MMP-9 mRNA expression in MCF-7 human breast carcinoma cells. However, the molecular mechanisms involved in transcriptional suppression of MMP-9 by HM in PMA-induced MCF-7 cells are not known. In this study, we aimed to elucidate the molecular mechanisms involved in the inhibition of MMP-9 expression by HM in PMA-induced MCF-7 cells. The results of promoter assay and EMSA showed that HM specifically inhibits MMP-9 gene expression by blocking PMA-stimulated activation of activator protein-1 (AP-1). In addition, PMA-stimulated phosphorylation of extracellular signal regulated kinase1/2 (ERK1/2) was suppressed by HM treatment, whereas the phosphorylation of either c-Jun N-terminal kinase (JNK) or p38 mitogen-activated protein kinase (MAPK) was not affected. HM could inhibit the PMA-induced MMP-9 expression through suppression of the transcriptional activity of MMP-9 gene in MCF-7 cells. These results indicate that HM inhibits PMA-induced MMP-9 expression by blocking the activation of activator protein-1 (AP-1) via extracellular signal regulated kinase1/2 (ERK 1/2) signaling pathway.

N-Glycomic Changes in Human Breast Carcinoma MCF-7 and T-Lymphoblastoid Cells After Treatment with Herceptin and Herceptin/Lipoplex

The humanized monoclonal antibody IgG1 in combination with chemotherapy has been demonstrated to enhance survival benefit in cancer treatment. Despite positive outcomes, some cancer cells develop multidrug resistance. Numerous mechanisms in cancers can be involved in the process of treatment therapy and most of them are not still well understood. To address how the carbohydrate moieties of cells are affected during treatment, the glycan profiles from the two most common cancer cell lines - human breast MCF-7 carcinoma and T-lymphoblastoid CEM cells - were studied here and compared with profiles after treatment with Herceptin alone or in combination with Lipofectamine mixed with plasmid DNA to form Lipoplex. N-Glycans were released from total cells by digestion with PNGaseF and analyzed by matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS). In summary, both original cell lines showed a dominant occurrence of high-mannose glycans. After treatment, these structures were suppressed and biantennary core-fucosylated glycans originating from IgG1 were the major carbohydrate products identified in cells. The high incidence of additional fucosylated or nonfucosylated galactosylated oligosaccharides, which were not detected in original cells or Herceptin, varied with conditions and time of exposure of cells to the antibody. The results presented in this study provide strong evidence for a role of glycosylation during antibody treatment.

Toxicity of (22R,23R)-22,23-dihydroxystigmastane derivatives to cultured cancer cells

Toxicity of eight 22,23-dihydroxystigmastane derivatives (four pairs of (22R,23R)- and (22S,23S)-isomers differing in steroid backbone structure) to human breast carcinoma MCF-7 cells was compared. For every pair of structurally related compounds, (22R,23R) isomer was found to be significantly more toxic than (22S,23S) isomer. Computational analysis showed that side chain of (22R,23R)-22,23-dihydroxystigmastane derivatives is rigid, whereas that of (22S,23S)-isomers is rather flexible. Structure of steroid backbone significantly affects cytotoxicity of (22R,23R)-22,23-dihydroxystigmastane derivatives to human breast carcinoma MCF-7 cells, human ovary carcinoma CaOv cells, and human prostate carcinoma LnCaP cells. (22R,23R)-3β,22,23-trihydroxystigmast-5-ene and (22R,23R)-3β,22,23-trihydroxystigmast-5-en-7-one, both comprising equatorial 3β-hydroxyl group, exhibited the highest cytotoxicity, while the most polar 28-homobrassinolide and 28-homocastasterone, both comprising 2α,3α-dihydroxy groups, exhibited the lowest toxicity. Binding of (22R,23R)-22,23-dihydroxystigmastane derivatives to plasmatic membrane was suggested to be important for cytotoxicity.

Grape Seed Proanthocyanidins Ameliorate Doxorubicin-Induced Cardiotoxicity

Doxorubicin (Dox) is one of the most widely used and successful chemotherapeutic antitumor drugs. Its clinical application is highly limited due to its cumulative dose-related cardiotoxicity. Proposed mechanisms include the generation of reactive oxygen species (ROS)-mediated oxidative stress. Therefore, reducing oxidative stress should be protective against Dox-induced cardiotoxicity. To determine whether antioxidant, grape seed proanthocyanidin extract (GSPE) attenuates Dox-induced ROS generation and protects cardiomyocytes from Dox-induced oxidant injury, cultured primary cardiomyocytes were treated with doxorubicin (Dox, 10 microM) alone or GSPE (50 microg/ml) with Dox (10 microM) for 24 hours. Dox increased intracellular ROS production as measured by 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate, induced significant cell death as assessed by propidium iodide, and declined the redox ratio of reduced glutathione (GSH)/oxidized glutathione (GSSG) and disrupted mitochondrial membrane potential as determined by 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethlbenzimidazole-carbocyanide iodine (JC-1). Analysis of agarose gel electrophoresis revealed Dox-induced nuclear DNA damage with the ladder like fragmentation. GSPE treatment suppressed those alterations. Electron Spin Resonance (ESR) spectroscopy data also showed that GSPE strongly scavenged hydroxyl radical, superoxide and DPPH radicals. Together, these findings indicate that GSPE in combination with Dox has protective effect against Dox-induced toxicity in cardiomyocytes, which may be in part attributed to its antioxidative activity. Importantly, flow cytometric analysis demonstrated that co-treatment of Dox and GSPE did not decrease the proliferation-inhibitory effect of Dox in MCF-7 human breast carcinoma cells. Thus, GSPE may be a promising adjuvant to prevent cardiotoxicity without interfering with antineoplastic activity during chemotherapeutic treatment with Dox.

Estrogenic activities of two synthetic pyrethroids and their metabolites

Synthetic pyrethroids (SPs) are among the most common pesticides in current use, and so far, several SPs have been assessed for their potential estrogenicities by various methods. Previous studies have shown that the estrogenicities partly come from their metabolites. Although considerable information is available with respect to the metabolism and environmental degradation of SPs, little is known about the estrogenicities of the metabolites. In this study, permethrin (PM) and β-cypermethrin (CP), as well as their metabolites (3-phenoxybenzoic alcohol (PBCOH), 3-phenoxybenzaldehyde (PBCHO) and 3-phenoxybenzoic acid (PBCOOH) were evaluated for their estrogenic activities in the MCF-7 human breast carcinoma cell line. In the MCF-7 cell proliferation assay, PM and CP exhibited significant estrogenic activities at 10 −7 mol/L, comparable to 17β-estradiol (E 2) of 10 −9 mol/L, with the relative proliferative effect ratios of 55.4% and 56.3%, respectively. The real-time quantitative polymerase chain reaction (qRT-PCR) results confirmed the estrogenicities of PM and CP with significant alteration of pS2 and ERα mRNA levels observed at 10 −6 mol/L. For the three major metabolites, PBCOH and PBCOOH exhibited estrogenic activities in all assays, while no significant estrogenic responses was observed for PBCHO compared to the vehicle control. In particular, PBCOH had even slightly stronger estrogenic activity than its parent compounds, indicating that metabolism may be one of the reasons for the estrogenicities of the SPs. Given the widespread use of SPs, the toxicological effects of parent compounds and their metabolites should be taken into consideration in the risk assessment of SPs.

Effect of Modulation of hnRNP L Levels on the Decay of bcl-2 mRNA in MCF-7 Cells

It has been shown that CA repeats in the 3'-untranslated region (UTR) of bcl-2 mRNA contribute the constitutive decay of bcl-2 mRNA and that hnRNP L (heterogenous nuclear ribonucleoprotein L) interacts with CA repeats in the 3'-UTR of bcl-2 mRNA, both in vitro and in vivo. The aim of this study was to determine whether the alteration of hnRNP L affects the stability of bcl-2 mRNA in vivo. Human breast carcinoma MCF-7 cells were transfected with hnRNP L-specific shRNA or hnRNP L-expressing vector to decrease or increase hnRNP L levels, respectively, followed by an actinomycin D chase. An RT-PCR analysis showed that the rate of degradation of endogenous bcl-2 mRNA was not affected by the decrease or increase in the hnRNP L levels. Furthermore, during apoptosis or autophagy, in which bcl-2 expression has been reported to decrease, no difference in the degradation of bcl-2 mRNA was observed between control and hnRNP L-knock down MCF-7 Cells. On the other hand, the levels of AUF-1 and nucleolin, transacting factors for ARE in the 3'UTR of bcl-2 mRNA, were not significantly affected by the decrease in hnRNP L, suggesting that a disturbance in the quantitative balance between these transacting factors is not likely to interfere with the effect of hnRNP L. Collectively, the findings indicate that the decay of bcl-2 mRNA does not appear to be directly controlled by hnRNP L in vivo.

Synthesis, molecular structure, and validation of metalloprobes for assessment of MDR1 P-glycoprotein-mediated functional transport

The human genome is known to consist of 49 ATP-binding cassette (ABC) transporter genes. Among these ABC proteins, overexpression of multidrug resistance (MDR1) P-glycoprotein (Pgp/ABCB1) is the best characterized barrier to successful chemotherapeutic treatments, impacts pharmacokinetics of numerous recognized drugs, and is also quickly emerging as an important target in the development of neurodegenerative diseases. Therefore, there exists an urgent need to seek radiopharmaceuticals, incorporated with generator-produced radionuclides to assist their widespread deployment, for noninvasive assessment of Pgp-mediated functional transport activity in vivo. gallium(III) complexes (5a and 5b) possessing octahedral geometry were synthesized, analytically characterized, and evaluated for their potential to serve as probes of Pgp-mediated functional transport activity in cellulo and in vivo. While unlabeled compounds (5a and 5b) were examined via cell cytotoxicity assays, the (67)Ga-labeled counterparts (6a and 6b) were evaluated via cell transport studies and quantitative biodistribution studies in mdr1a/1b((-/-)) gene-deleted mice and their wild-type (WT) counterparts. cytotoxicity data of 5a and 5b displayed profiles modified by the expression of Pgp in drug-resistant cells. (67)Ga-metalloprobes (6a and 6b) showed high accumulation in human epidermal carcinoma drug-sensitive KB-3-1 cells (Pgp-), human breast carcinoma MCF-7 (Pgp-) cells; an inhibitor (LY335979, 1 microM) induced accumulation in multidrug resistant (MDR, Pgp+) KB-8-5, KB-8-5-11 cells, and stably transfected MCF-7/MDR1 cells, thus demonstrating their ability to interrogate Pgp-mediated functional transport activity in cellulo. In mdr1a/1b((-/-)) gene-deleted mice, the (67)Ga-metalloprobe (6b) showed 8-fold greater brain uptake and retention compared with WT counterparts and no significant difference in blood pharmacokinetics. molecular imaging of the functional transport activity of MDR1 Pgp (ABCB1) with (67/68)Ga-metalloprobes could enable non-invasive monitoring of the blood-brain barrier, tumors, and tissues in vivo.